[fckgnad]

>This. The educational system, willingly or just incompetently manages to instill a sense that human intelligence somehow grows monotonically with historical time.

Several remarks here. It is growing with time. Average IQ grows every year such that they have to re-normalize it all the time. This is on a very short timescale though.

Second, there is logic behind an actual theory that prehistoric humans were actually SMARTER then modern day humans. A human back in the day had much more to deal with in order to survive. Nowadays you can get away with working at menial and repetitive jobs. This implies that there is less recent evolutionary pressure for maintaining high intelligence indicating at the possibility of humans becoming stupider in modern times.